Web export requirements

Vapour publishes browser builds, not desktop executables. Your export must contain an index.html, its JavaScript modules, any Wasm it uses and required game assets. A pure JavaScript game does not need to add a fake .wasm file.

build/web/
  index.html
  game.js
  game.wasm
  assets/...

Actual names vary by engine. Preserve the relative layout your generated HTML expects. Use relative asset URLs where practical so the build works under a game-specific /play/<slug>/ path. Opening the HTML from file:// is not a representative hosting test.

Packaging rules

Status: planned: chunked large-game delivery will target 50 GiB/game and 4 GiB/file. These higher limits are not current support; the existing ZIP limits below still apply. Chunking does not lift engine memory limits.

The source-preview API accepts a ZIP up to 512 MiB, with at most 5,000 entries and 1 GiB uncompressed. It rejects path traversal, absolute paths, backslash paths and builds without index.html. A single wrapping top-level directory can be stripped by the server. Prefer index.html directly at the root to keep local and server validation consistent.

The CLI checks and ZIPs a build directory. If given a prebuilt ZIP, it uploads it as-is after ZIP/size checks; it does not repeat every server extraction check. --dry-run is useful but not a promise that every ZIP will be accepted remotely.

Optional cover upload: maximum 5 MiB; use a supported image such as PNG, JPEG or WebP. Keep covers separate from the engine's runtime asset bundle when practical.

Browser hosting details

• Wasm needs Content-Type: application/wasm for normal streaming compilation.
• Compressed Unity exports need matching serving/decompression behavior.
• Threads/SharedArrayBuffer require actual cross-origin isolation, including subresource headers. Check crossOriginIsolated in the game frame.
• The sandboxed iframe must be the context in which game telemetry runs. Measuring rAF or memory on the surrounding dashboard does not profile the game.

Choose your engine guide: Godot, Unity, Bevy, JavaScript frameworks or other exporters.